Electrophotographic photoconductors and tertiary amine compounds having condensed polycyclic group for use in the same

ABSTRACT

An electrophotographic photoconductor comprising an electroconductive support, and a photoconductive layer formed thereon comprising at least one tertiary amine compound having a condensed polycyclic hydrocarbon group of formula (I): ##STR1## wherein A 1  and A 2  each independently represent an unsubstituted or substituted alkyl group or aryl group, and Ar represents an unsubstituted or substituted condensed polycyclic hydrocarbon group. Furthermore, novel tertiary amine compounds having a condensed polycyclic hydrocarbon group are disclosed.

This is a divisional of application Ser. No. 08/015,339 filed Feb. 9,1993, now U.S. Pat. No. 5,382,692, which is a divisional of applicationSer. No. 07/490,468 filed Mar. 8, 1990, now U.S. Pat. No. 5,219,692.

BACKGROUND OF THE INVENTION

1. Field of the Invention

This invention relates to electrophotographic photoconductors, and moreparticularly to electrophotographic photoconductor whose photoconductivelayer comprises at least one tertiary amine compound having a condensedpolycyclic hydrocarbon group, and to tertiary amine compounds having apolycyclic hydrocarbon group which can be used as photoconductivematerials in the photoconductors.

2. Discussion of Background

Conventionally, inorganic materials such as selenium, cadmium sulfideand zinc oxide are used as photoconductive materials of anelectrophotographic photoconductor in the electrophotographic process.The above-mentioned electrophotographic process is one of the imageforming processes, through which the surface of the photoconductor ischarged uniformly in the dark to a predetermined polarity, for instance,by corona charge. The uniformly charged photoconductor is exposed to alight image to selectively dissipate the electrical charge of theexposed areas, so that a latent electrostatic image is formed on thephotoconductor. The thus formed latent electrostatic image is developedby a developer comprising a coloring agent such as a dye and a pigment,and a binder agent such as a polymeric material, to a visible image.

Fundamental characteristics required for the photoconductor in such anelectrophotographic process are:

(1) chargeability to an appropriate potential in the dark,

(2) minimum dissipation of electrical charge in the dark, and

(3) rapid dissipation of electrical charge when exposed to the light.

However, while the above-mentioned inorganic materials have manyadvantages, they have several shortcomings form the viewpoint ofpractical use.

For instance, a selenium photoconductor, which is widely used atpresent, completely satisfies the above-mentioned requirements (1) to(3), but it has the short-comings that its manufacturing conditions aredifficult to control, and accordingly its production cost is high. Inaddition, it is difficult to work it into the form of a belt due to itspoor flexibility, and it is so vulnerable to heat and mechanical shocksthat it must be handled with the utmost care.

A cadmium sulfide photoconductor and a zinc oxide photoconductor can beeasily obtained by coating a dispersion of cadmium sulfide particles andzinc oxide particles in a binder resin on a support. However, they arepoor in mechanical properties, such as surface smoothness, hardness,tensile strength and wear resistance. Therefore, they cannot be used inthe repeated operation, as they are.

To solve the above-mentioned problems of the inorganic materials,various electrophotographic photoconductors employing organic materialsare proposed recently and some are put to practical use. For example,there are known a photoconductor comprising poly-N-vinylcarbazole and2,4,7-trinitrofluorene-9-on, as disclosed in U.S. Pat. No. 3,484,237; aphotoconductor prepared by sensitizing poly-N-vinylcarbazole with apigment of pyrylium salt, as disclosed in Japanese Patent Publication48-25658; a photoconductor comprising as the main component an organicpigment, as disclosed in Japanese Laid-Open Patent Application 47-37543;a photoconductor comprising as the main component an eutectic crystalcomplex of a dye and a resin, as disclosed in Japanese Laid-Open PatentApplication 47-10735; a photoconductor prepared by sensitizing atriphenylamine compound with a sensitizer pigment, as disclosed in U.S.Pat. No. 3,180,730; a photoconductor comprising an amine derivative as acharge transporting material as disclosed in Japanese Laid-Open PatentApplication 57-195254, a photoconductor comprising poly-N-vinylcarbazoleand an amine derivative as a charge transporting material, as disclosedin Japanese Laid-Open Patent Application 58-1155, and photoconductorscomprising as a photoconductive material a polyfunctional tertiary aminecompound, especially a benzidine compound, as disclosed in U.S. Pat. No.3,265,496, Japanese Patent Publication 39-11546 and Japanese Laid-OpenPatent Application 53-27033.

Although the above photoconductors have excellent characteristics, andcan be put in practical use, they are still unsatisfactory asphotoconductors for use in electrophotography.

SUMMARY OF THE INVENTION

It is therefore a first object of the present invention to provide anelectrophotographic photoconductor having good durability, free from theconventional shortcomings, which can completely satisfy all therequirements in the electrophotographic process, and can be easilymanufactured at relatively low cost.

A second object of the present invention is to provide a chargetransporting material for use in the above-mentioned electrophotographicphotoconductor.

A third object of the present invention is to provide novel tertiaryamine compounds having a condensed polycyclic hydrocarbon group used asphotoconductive materials in the electrophotographic photoconductor.

The first object of the present invention can be achieved by anelectrophotographic photoconductor comprising an electroconductivesupport and a photoconductive layer formed thereon comprising at leastone tertiary amine compound having a condensed polycyclic hydrocarbongroup, represented by formula (I): ##STR2## in which A¹ and A² eachindependently represent an unsubstituted or substituted alkyl or arylgroup, and Ar represents an unsubstituted or substituted condensedpolycyclic hydrocarbon group.

The second object of the present invention can be attained by a chargetransporting material for use in the electrophotographic photoconductor,which comprises a tertiary amine compound having the above-mentionedformula (I).

The third object of the present invention can be attained by tertiaryamine compounds having formula (II): ##STR3## wherein Ar' represents acondensed polycyclic hydrocarbon group having 18 or less carbon atoms,R¹ and R² each independently represent hydrogen, an unsubstituted orsubstituted alkyl group, an unsubstituted or substituted alkoxyl group,or an unsubstituted or substituted phenyl group.

BRIEF DESCRIPTION OF THE DRAWINGS

A more complete appreciation of the invention and many of the attendantadvantageous thereof will be readily obtained as the same become betterunderstood by reference to the following detailed description whenconsidered in connection with the accompanying drawings, wherein:

FIG. 1 is a chart of an infrared absorption spectrum, taken by the KBrtablet method, of the tertiary amine compound having a condensedpolycyclic group according to the present invention prepared inSynthesis Example 1;

FIG. 2 is a chart of an infrared absorption spectrum, taken by the KBrtablet method, of the tertiary amine compound having a condensedpolycyclic group according to the present invention prepared inSynthesis Example 4;

FIG. 3 is a chart of an infrared absorption spectrum, taken by the KBrtablet method, of the tertiary amine compound having a condensedpolycyclic group according to the present invention prepared inSynthesis Example 7;

FIG. 4 is a chart of an infrared absorption spectrum, taken by the KBrtablet method, of the tertiary amine compound having a condensedpolycyclic group according to the present invention prepared inSynthesis Example 8;

FIG. 5 is a chart of an infrared absorption spectrum, taken by the KBrtablet method, of the tertiary amine compound having a condensedpolycyclic group according to the present invention prepared inSynthesis Example 9;

FIG. 6 is a chart of an infrared absorption spectrum, taken by the KBrtablet method, of the tertiary amine compound having a condensedpolycyclic group according to the present invention prepared inSynthesis Example 10;

FIG. 7 is a chart of an infrared absorption spectrum, taken by the KBrtablet method, of the tertiary amine compound having a condensedpolycyclic group according to the present invention prepared inSynthesis Example 13;

FIG. 8 is a schematic cross-sectional view of an electrophotographicphotoconductor according to the present invention; and

FIGS. 9 through 13 are schematic cross-sectional views of otherpreferred electrophotographic photoconductors according to the presentinvention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

According to the present invention, an electrophotographicphotoconductor comprising an electroconductive support and aphotoconductive layer formed thereon, which photoconductive layercomprises at least one tertiary amine compound having a condensedpolycyclic hydrocarbon group represented by the following formula (I) isprovided: ##STR4## in which A¹ and A² each independently represent anunsubstituted or substituted alkyl or aryl group, and Ar represents anunsubstituted or substituted condensed polycyclic hydrocarbon group.

A more specific explanation of the tertiary amine compound, representedby formula (I), is given below.

A preferred condensed polycyclic hydrocarbon group represented by Ar informula (I) is a group having a ring consisting of 18 or less carbonatoms; for instance, a pentalenyl group, an indenyl group, a naphthylgroup, an azulenyl group, a heptalenyl group, a biphenylenyl group, anas-indacenyl group, a fluorenyl group, an s-indacenyl group, anacenaphthylenyl group, a pleiadenyl group, an acenaphthenyl group, aphenalenyl group, a phenanthryl group, an anthryl group, a fluoranthenylgroup, an acephenanthrylenyl group, an aceanthrylenyl group, atriphenyienyl group, a pyrenyl group, a chrysenyl group and anaphthacenyl group.

Ar may have any of the following groups as a substituent.

(1) A halogen, a cyano group, and a nitro group.

(2) A linear or branched alkyl group having 1 to 12 carbon atoms,preferably 1 to 8 carbon atoms, and more preferably 1 to 4 carbon atoms.The alkyl group may have as a substituent fluorine, a hydroxyl group, acyano group, an alkoxyl group having 1 to 4 carbon atoms, or a phenylgroup which may have a substituent such as a halogen, an alkyl grouphaving 1 to 4 carbon atoms, or an alkoxyl group having 1 to 4 carbonatoms.

Specific examples of the alkyl group include a methyl group, an ethylgroup, a n-propyl group, an i-propyl group, a t-butyl group, a s-butylgroup, a n-butyl group, an i-buryl group, a trifluoromethyl group, a2-hydroxyethyl group, a 2-cyanoethyl group, a 2-ethoxyethyl group, a2-methoxyethyl group, a benzyl group, a 4-chlorobenzyl group, a4-methylbenzyl group, a 4-ethoxybenzyl group and a 4-phenylbenzyl group.

(3) An alkoxyl group represented by -OR¹.

R¹ represents an alkyl group defined in the above item (2).

Specific examples of the alkoxyl group include a methoxy group, anethoxy group, a n-propoxy group, an i-propoxy group, a t-butoxy group, an-butoxy group, a s-butoxy group, an i-butoxy group, a 2-hydroxyethoxygroup, a 2-cyanoethoxy group, a benzyloxy group, a 4-methylbenzyloxygroup and a trifluoromethoxy group.

(4) An aryloxy group.

An aryl group in the aryloxy group is a phenyl group or a naphthylgroup. The aryl group may have as a substituent an alkoxyl group having1 to 4 carbon atoms, an alkyl group having 1 to 4 carbon atoms, or ahalogen.

Specific examples of the aryloxy group include a phenoxy group, a1-naphthyloxy group, a 2-naphthyloxy group, a 4-methylphenoxy group, a4-methoxyphenoxy group, a 4-chlorophenoxy group and a6-methyl-2-naphthyloxy group.

(5) An alkytmercapto group or a phenylmercapto group represented by-SR¹.

R¹ represents an alkyl group defined in the above item (2), or a phenylgroup which may have a substituent.

Specific examples of the alkylmercapto group and the phenylmercaptogroup include a methylthio group, an ethylthio group, a phenylthio groupand a p-methyl-phenylthio group.

(6) A group represented by ##STR5## wherein R² and R³ each independentlyrepresent hydrogen, an alkyl group defined in the above item (2), or anaryl group such as a phenyl group, a biphenylyl group or a naphthylgroup. The aryl group may have as a substituent an alkoxyl group having1 to 4 carbon atoms, an alkyl group having 1 to 4 carbon atoms, or ahalogen. R² can form a ring along with R³, or R² and R³ can form a ringalong with a carbon atom contained in the aryl group.

Specific examples of the group represented by the above formula includean amino group, a diethylamino group, an N-methyl-N-phenylamino group,an N,N-diphenylamino group, an N,N-di(p-tolyl)amino group, adibenzylamino group, a piperidino group, a morpholino group and ajulolidyl group.

(7) A methylene dioxy group, and an alkylene dioxy group or an alkylenedithio group such as a methylene dithio group.

The aryl group represented by A¹ or A² in formula (I) may be acarbocyclic aromatic group or a heterocyclic aromatic group.

Examples of the carbocyclic aromatic group include non-condensedcarbocyclic aromatic groups such as a phenyl group, a biphenylyl groupand a terphenyl group, and condensed polycyclic hydrocarbon groups.

Examples of the condensed polycyclic hydrocarbon groups are the same asthose represented by Ar defined before.

These aryl groups may have as a substituent any of the groups describedin the above items (1) through (7).

Examples of the heterocyclic aromatic groups include a pyridyl group, apyrimidyl group, a pyrazinyl group, a triazinyl group, a furanyl group,a pyrrolyl group, a thiophenyl group, a quinolyl group, a coumarinylgroup, a benzofuranyl group, a benzimidazolyl group, a benzoxazolylgroup, a dibenzofuranyl group, a benzothiophenyl group, adibenzothiophenyl group, an indolyl group, a carbazolyl group, apyrazolyl group, an imidazolyl group, an oxazolyl group, an isooxazolylgroup, a thiazolyl group, an indazolyl group, a benzothiazolyl group, apyridazinyl group, a cinnolyl group, a quinazolyl group, a quinoxalylgroup, a phthalazinyl group, a phthalazinedionyl group, a phthalamidylgroup, a chromonyl group, a naphtholactamyl group, a quinolonyl group,an o-sulfobenzoic acid imidyl group, a maleic acid imidyl group, anaphthalidinyl group, a benzimidazonyl group, a benzoxazonyl group, abenzothiazolonyl group, a benzothiazothionyl group, a quinazolonylgroup, a quinoxalonyl group, a phthalazonyl group, a dioxopyrimidinylgroup, a pyridonyl group, an isoquinoionyl group, an isoquinolinylgroup, an isothiazolyl group, a benzisooxazolyl group, abenzisothiazolyl group, an indazolonyl group, an acridinyl group, anacridonyl group, a quinazolienedionyl group, a quinoxalinedionyl group,a benzoxadine dionyl group, a benzoxadinolyl group and naphthalimidylgroup.

The substituted or unsubstituted alkyl group represented by A¹ or A² informula (I) is the same as those defined in the above item (2).

The tertiary amine compounds having a condensed polycyclic hydrocarbongroup of formula (I) can be prepared by reacting a condensed polycyclichydrocarbon compound substituted with an amino group, represented byformula (III):

    Ar--NH.sub.2                                               (III)

wherein Ar represents an unsubstituted or substituted condensedpolycyclic hydrocarbon group, with a halogenated compound represented byformula (IV):

    X--A                                                       (IV)

wherein A represents a substituted or unsubstituted alkyl or aryl group,and X represents a halogen, or reacting a condensed polycyclichydrocarbon compound substituted with a halogen, represented by formula(V):

    Ar--X                                                      (V)

wherein Ar is the same as defined above, and X represents a halogen,with an amino compound represented by formula (VI) ##STR6## wherein A¹and A² each independently represent a substituted or unsubstituted alkylor aryl group.

Representative examples of the tertiary amine compounds having thecondensed polycyclic hydrocarbon group for use in electrophotographicphotoconductors according to the present invention are shown in Table 1.

                                      TABLE 1                                     __________________________________________________________________________    Compound No.                                                                          Formula                   Melting Point (°C.)                  __________________________________________________________________________     (1)                                                                                   ##STR7##                 181.0-181.5                                  (2)                                                                                   ##STR8##                 136.5-137.5                                  (3)                                                                                   ##STR9##                 214.0-215.0                                  (4)                                                                                   ##STR10##                167.0-168.0                                  (5)                                                                                   ##STR11##                239.0-240.0                                  (6)                                                                                   ##STR12##                173.0-174.0                                  (7)                                                                                   ##STR13##                173.0-174.0                                  (8)                                                                                   ##STR14##                127.0-128.0                                  (9)                                                                                   ##STR15##                oily material                               (10)                                                                                   ##STR16##                139.0-140.0                                 (11)                                                                                   ##STR17##                94.0-95.5                                   (12)                                                                                   ##STR18##                137.0-138.0                                 (13)                                                                                   ##STR19##                225.5-226.0                                 (14)                                                                                   ##STR20##                150.5-151.5                                 (15)                                                                                   ##STR21##                130.5-131.5                                 (16)                                                                                   ##STR22##                196.5-197.5                                 (17)                                                                                   ##STR23##                155.5-156.5                                 __________________________________________________________________________

In particular, among the tertiary amine compounds having a condensedpolycyclic group represented by formula (I), those compounds having Arwhich represents a condensed polycyclic hydrocarbon group having 18 orless carbon atoms, A¹ and A² which independently represent an aryl grouphaving as a substituent hydrogen, a substituted or unsubstituted alkylgroup, a substituted or unsubstituted alkoxyl group, or a substituted orunsubstituted phenyl group are novel. Namely, such novel compounds arerepresented by the following formula (II): ##STR24## wherein Ar'represents a condensed polycyclic group having 18 or less carbon atoms,R¹ and R² each independently represent hydrogen, a substituted orunsubstituted alkyl group, a substituted or unsubstituted alkoxyl group,or a substituted or unsubstituted phenyl group.

Specific examples of Ar' in formula (II) include a naphthyl group, afluorenyl group, an acenaphthenyl group, an anthryl group, a pyrenylgroup, a phenanthryl group, a chrysenyl group and a fluoranthenyl group.

Specific examples of the alkyl group represented by R¹ or R² include analkyl group having 1 to 6 carbon atoms, such as a methyl group, an ethylgroup, a propyl group and a butyl group.

Specific examples of the alkoxyl group represented by R¹ or R² includean alkoxyl group having 1 to 6 carbon atoms such as a methoxy group, anethoxy group and a propoxy group.

The alkyl group represented by R¹ or R² may have as a substituent aphenyl group, a halogen, an alkoxyl group or an aryloxy group.

The phenyl group represented by R¹ or R² may have as a substituent analkyl group having 1 to 6 carbon atoms, such as a methyl group, an ethylgroup, a propyl group or a butyl group, an alkoxyl group having 1 to 6carbon atoms such as a methoxy group, an ethoxy group or a propoxygroup, or a halogen such as bromine or chlorine.

The tertiary amine compound having a condensed polycyclic group,represented by formula (II), can be prepared by reacting an aminocondensed polycyclic hydrocarbon derivative represented by formula(III'):

    Ar'--NH.sub.2                                              (III')

wherein Ar' is the same as defined above, with a halobenzene derivativerepresented by formula (III'): ##STR25## wherein R¹ and R² are the sameas defined above, and X represents a halogen, or by reacting ahalocondensed polycyclic hydrocarbon derivative represented by formula(V'):

    Ar'--X                                                     (V')

wherein Ar' and X are the same as defined above, with a diphenyl aminederivative represented by formula (V'): ##STR26## wherein R¹ and R² arethe same as defined above.

In the above reaction, copper powder, copper oxide or halogenated copperwhich serves as a catalyst, and an alkaline material or an alkali saltare added to the reaction system. The amount of the alkaline material orthe alkali salt is such that the hydrogen halogenide produced during thecondensation reaction can be completely neutralized.

The reaction proceeds in the presence or absence of a solvent under anitrogen atmosphere. The reaction temperature is approximately 150° to250° C.

Examples of the alkaline material added to the reaction system includesodium hydroxide, and potassium hydroxide, and examples of the alkalisalt include sodium carbonate and potassium carbonate.

Examples of the solvent usable for the above reaction includenitrobenzene, dichlorobenzene, quinoline, N,N-dimethylformamide,dimethylsulfoxide, N-methyl pyrrolidone and1,3-dimethyl-2-imidazolidinon.

The above-mentioned tertiary amine compounds having condensed polycyclicgroup for use in the present invention, which are remarkably effectiveas photoconductive materials in the electrophotographic photoconductor,are optically or chemically sensitized with a sensitizer such as a dyeor Lewis acid. In addition, the tertiary amine compounds effectivelyfunction as charge transporting materials in a function-separating typeelectrophotographic photoconductor where an organic or inorganic pigmentserves as a charge generating material.

In the photoconductors according to the present invention, at least onetertiary amine compound of formula (I) is contained in thephotoconductive layers 2, 2a, 2b, 2c, 2d and 2e. The tertiary aminecompounds can be employed in different ways, for example, as shown inFIGS. 8 through 13.

In the photoconductor as shown in FIG. 8, a photoconductive layer 2 isformed on an electroconductive support 1, which photoconductive layer 2comprises a tertiary amine compound, a sensitizing dye and a binderagent (binder resin). In this photoconductor, the tertiary aminecompound works as a photoconductive material, through which chargecarriers necessary for the light decay of the photoconductor aregenerated and transported. However, the tertiary amine compound itselfscarcely absorbs light in the visible light range and, therefore, it isnecessary to add a sensitizing dye which absorbs light in the visiblelight range in order to form latent electrostatic images by use ofvisible light.

Referring to FIG. 9, there is shown an enlarged cross-sectional view ofanother embodiment of an electrophotographic photoconductor according tothe present invention. In the figure, reference numeral 1 indicates anelectroconductive support. On the electroconductive support 1, there isformed a photoconductive layer 2a comprising a charge generatingmaterial 3 dispersed in a charge transporting medium 4 comprising atertiary amine compound and a binder agent. In this embodiment, thetertiary amine compound and the binder agent (or a mixture of the binderagent and a plasticizer) constitute the charge transporting medium 4 incombination. The charge generating material 3, which is, for example, aninorganic or organic pigment, generates charge carriers. The chargetransporting medium 4 accepts the charge carriers generated by thecharge generating material 3 and transports those charge carriers.

In this electrophotographic photoconductor, it is basically requiredthat the light-absorption wavelength regions of the charge generatingmaterial 3 and the tertiary amine compound do not overlap in the visiblelight range. This is because, in order that the charge generatingmaterial 3 produce charge carriers efficiently, it is necessary thatlight pass through the charge transporting medium 4 and reach thesurface of the charge generating material 3. Since the tertiary aminecompounds of the previously described formula (I) do not substantiallyabsorb light in the visible range, they can work effectively as chargetransporting materials in combination with the charge generatingmaterial 3 which absorbs the light in the visible region and generatescharge carriers.

Referring to FIG. 10, there is shown an enlarged cross-sectional view ofa further embodiment of an electrophotographic photoconductor accordingto the present invention. In the figure, there is formed on anelectroconductive support 1 a two-layered photoconductive layer 2bcomprising a charge generation layer 5 containing a charge generatingmaterial 3, and a charge transport layer 4 containing a tertiary aminecompound of the previously described formula (I).

In this photoconductor, light which has passed through the chargetransport layer 4 reaches the charge generation layer 5, and chargecarriers are generated within the charge generation layer 5. The chargecarriers which are necessary for the light decay for latentelectrostatic image formation are generated by the charge generatingmaterial 3, accepted and transported by the charge transport layer 4. Inthe charge transport layer 4, the tertiary amine compound mainly worksfor transporting charge carriers. The generation and transportation ofthe charge carriers are performed by the same mechanism as that in thephotoconductor shown in FIG. 3.

In an electrophotographic photoconductor shown in FIG. 11, a chargegeneration layer 5 is formed on a charge transport layer 4 containing atertiary amine compound in a photoconductive layer 2c, thus theoverlaying order of the charge generation layer 5 and the chargetransport layer 4 is reversed as compared with the electrophotographicphotoconductor as shown in FIG. 10. The mechanism of the generation andtransportation of charge carriers is substantially the same as that ofthe photoconductor shown in FIG. 10.

In the above photoconductor, a protective layer 6 may be formed on thecharge generation layer 5 as shown in FIG. 12 for protecting the chargegeneration layer 5.

When the electrophotographic photoconductor according to the presentinvention as shown in FIG. 8 is prepared, at least one tertiary aminecompound of the previously described formula (I) is dispersed in abinder resin solution, and a sensitizing dye is then added to themixture, so that a photoconductive layer coating liquid is prepared. Thethus prepared photoconductive layer coating liquid is coated on anelectroconductive support 1 and dried, so that a photoconductive layer 2is formed on the electroconductive support 1.

It is preferable that the thickness of the photoconductive layer 2 be inthe range of 3 to 50 μm, more preferably in the range of 5 to 20 μm. Itis preferable that the amount of the tertiary amine compound containedin the photoconductive layer 2 be in the range or 30 to 70 wt. %, morepreferably about 50 wt. %.

It is preferable that the amount of the sensitizing dye contained in thephotoconductive layer 2 be in the range of 0.1 to 5 wt. %, morepreferably in the range of 0.5 to 3 wt. %.

Specific examples of the sensitizing dye for use in the presentinvention include triarylmethane dyes such as Brilliant Green, VictoriaBlue B, Methyl Violet, Crystal Violet and Acid Violet 6B; xanthene dyessuch as Rhodamine B, Rhodamine 6G, Rhodamine G Extra, Eosin S,Erythrosin, Rose Bengale and Fluoresceine; thiazine dyes such asMethylene Blue; cyanine dyes such as cyanin; and pyrylium dyes such as2,6-diphenyl-4-(N,N-dimethylaminophenyl)thiapyrylium perchlorate andbenzopyrylium salts disclosed in Japanese Patent Publication 48-25658.

These sensitizing dyes may be used either alone or in combination.

The electrophotographic photoconductor shown in FIG. 9 can be obtainedby dispersing finely-divided particles of the charge generating material3 in a solution in which at least one tertiary amine compound for use inthe present invention and the binder agent are dissolved, coating theabove-prepared dispersion on the electroconductive support 1 and thendrying the same to form the photoconductive layer 2a.

It is preferable that the thickness of the photoconductive layer 2a bein the range of 3 to 50 μm, more preferably in the range of 5 to 20 μm.It is preferable that the amount of the tertiary amine compoundcontained in the photoconductive layer 2a be in the range of 10 to 95wt. %, more preferably in the range of 30 to 90 wt. %.

It is preferable that the amount of the charge generating material 3contained in the photoconductive layer 2a be in the range of 0.1 to 50wt. %, more preferably in the range of 1 to 20 wt. %.

Specific examples of the charge generating material 3 for use in thepresent invention include inorganic pigments such as selenium,selenium-tellurium, cadmium sulfide, cadmium sulfide-selenium andα-silicon; and organic pigments, such as C.I. Pigment Blue 25 (C.I.21180), C.I. Pigment Red 41 (C.I. 21200), C.I. Acid Red 52 (C.I. 45100),and C.I. Basic Red 3 (C.I. 45210); an azo pigment having a carbazoleskeleton (Japanese Laid-Open Patent Application 53-95033), an azopigment having a distyryl benzene skeleton (Japanese Laid-Open PatentApplication 53-133445), an azo pigment having a triphenylamine skeleton(Japanese Laid-Open Patent Application 53-132347), an azo pigment havinga dibenzothiophene skeleton (Japanese Laid-Open Patent Application54-21728), an azo pigment having an oxadiazole skeleton (JapaneseLaid-Open Patent Application 54-12742), an azo pigment having afluorenone skeleton (Japanese Laid-Open Patent Application 54-22834), anazo pigment having a bisstilbene skeleton (Japanese Laid-Open PatentApplication 54-17733), an azo pigment having a distyryl oxadiazoleskeleton (Japanese Laid-Open Patent Application 54-2129), and an azopigment having a distyryl carbazole skeleton (Japanese Laid-Open PatentApplication 54-14967); a phthalocyanine pigment such as C.I. PigmentBlue 16 (C.I. 74100); indigo pigments such as C.I. Vat Brown 5 (C.I.73410) and C.I. Vat Dye (C.I. 73030); and perylene pigments such asAlgol Scarlet B and Indanthrene Scarlet R (both made by Bayer Co.,Ltd.). These charge generating materials may be used either alone or incombination.

The electrophotographic photoconductor shown in FIG. 10 can be obtainedas follows:

The charge generating material is vacuum-deposited on theelectroconductive support 1, or the dispersion in which finely-dividedparticles of the charge generating material 3 are dispersed in anappropriate solvent, if necessary, together with the binder agent iscoated on the electroconductive support 1 and dried, so that the chargegeneration layer 5 is formed. When necessary, the charge generationlayer 5 is subjected to buffing to adjust the thickness thereof. On thethus formed charge generation layer 5, the coating solution in which atleast one tertiary amine compound and the binder agent are dissolved iscoated and dried, so that the charge transport layer 4 is formed. In thecharge generation layer 5, the same charge generating material asemployed in the above-mentioned photoconductive layer 2a can be used.

The thickness of the charge generation layer 5 is 5 μm or less, morepreferably 2 μm or less. It is preferable that the thickness of thecharge transport layer 4 be in the range of 3 to 50 μm, more preferablyin the range of 5 to 20 μm. When the charge generation layer 5 isobtained by coating the dispersion in which finely-divided particles ofthe charge generating material 3 are dispersed in an appropriate solventtogether with the binder agent, it is preferable that the amount offinely-divided particles of the charge generating material 3 containedin the charge generation layer 5 be in the range of 10 to 95 wt. %, morepreferably in the range of about 50 to 90 wt. %. It is preferable thatthe amount of the tertiary amine compound contained in the chargetransport layer 4 be in the range of 10 to 95 wt. %, more preferably inthe range of 30 to 90 wt. %.

The electrophotographic photoconductor shown in FIG. 11 can be obtainedas follows:

The coating solution in which the tertiary amine compound and the binderagent are dissolved is coated on the electroconductive support 1 anddried to form the charge transport layer 4. On the thus formed chargetransport layer 4, the dispersion prepared by dispersing finely-dividedparticles of the charge generating material 3 in the solvent, in whichthe binder agent is dissolved when necessary, is coated by spray coatingand dried to form the charge generation layer 5 on the charge transportlayer 4. The amount ratio of the components contained in the chargegeneration layer and charge transport layer is the same as previouslydescribed in FIG. 4.

The electrophotographic photoconductor shown in FIG. 12 can be obtainedby forming a protective layer 6 on the charge generation layer 5 asobtained in FIG. 5 by spray-coating of an appropriate resin solution. Asthe resins employed in the protective layer 6, the binder agents whichwill be described later can be used.

An electrophotographic photoconductor with a structure as shown in FIG.13 may also be employed in the present invention, which can be obtainedby forming a charge transport layer 4a, a charge generation layer 5, anda charge transport layer 4b (which layers may be collectively referredto as a photoconductive layer 2e) successively in that order on anelectroconductive support 1, in which either the charge transport layer4a or the charge transport layer 4b comprises at least one tertiaryamine compound and the other charge transport layer comprises a Lewisacid type charge transporting material, for example, fluorenonecompounds such as trichlorofluorenone and quinone derivatives.

Specific examples of the electroconductive support for theelectrophotographic photoconductor according to the present inventioninclude a metallic plate or foil made of aluminum, a plastic film onwhich a metal such as aluminum is deposited, and a sheet of paper whichhas been treated so as to be electroconductive.

Specific examples of the binder agent for use in the present inventionare condensation resins such as polyamide, polyurethane, polyester,epoxy resin, polyketone and polycarbonate; and vinyl copolymers such aspolyvinylketone, polystyrene, poly-N-vinylcarbazole and polyacrylamide.All the resins having insulating properties and adhesive force can beemployed. Some plasticizers may be added to the above-mentioned binderagent, when necessary. Examples of the plasticizer for use in thepresent invention are halogenated paraffin, polybiphenyl chloride,dimethylnaphthalene and dibutyl phthalate.

Furthermore, in the electrophotographic photoconductors according to thepresent invention, an adhesive layer or barrier layer may be interposedbetween the electroconductive support and the photoconductive layer whennecessary. Examples of the material for use in the adhesive layer orbarrier layer are polyamide, nitrocellulose and aluminum oxide. It ispreferable that the thickness of the adhesive layer or barrier layer be1 μm or less.

When copying is performed by use of the photoconductors according to thepresent invention, the surface of the photoconductor is chargeduniformly in the dark to a predetermined polarity. The uniformly chargedphotoconductor is exposed to a light image so that a latentelectrostatic image is formed on the photoconductor. The thus formedlatent electrostatic image is developed by a developer to a visibleimage, and when necessary, the developed image can be transferred to asheet of paper. The electrophotographic photoconductors according to thepresent invention have high photosensitivity and improved flexibility.

Other features of this invention will become apparent in the course ofthe following description of exemplary embodiments, which are given forillustration of the invention and are not intended to be limitingthereof.

Synthesis Example 1 [Synthesis of Tertiary Amine Compound No. 1 in Table1]

While conducting azeotropical dehydration in a stream of nitrogen usingan ester tube, a mixture of 2.17 g (0.01 mol) of 1-aminopyrene, 32.70 g(0.15 mol) of 4-iodine-toluene, 5.53 g (0.04 mol) of potassium carbonateand 0.32 g of copper powder was stirred at a temperature between 206° C.and 209° C. for 6 hours.

The resulting mixture was then cooled to room temperature, and filteredusing a Celite. Chloroform was added to the filtrate, and the resultingmixture was washed with water using a separatory funnel, and then driedusing magnesium sulfide. The dried mixture was condensed under reducedpressure to obtain an oily product reddish black in color.

The oily product was placed on a silica gel column and eluted with a 1:3mixed solvent of toluene and n-hexane. The eluate was recrystallizedfrom a mixed solvent of ethanol and ethylacetate, thereby obtaining 1.65g of the captioned compound, 1-N,N-bis(4-methylphenyl)amino pyrene, aslight yellow leaf-shaped crystals.

Yield: 41.6%

Melting Point: 181.0°-181.5° C.

    ______________________________________                                        Elementary Analysis: (for C.sub.30 H.sub.23 N)                                         % C         % H    % N                                               ______________________________________                                        Found:     90.64         5.61   3.68                                          Calculated:                                                                              90.64         5.83   3.53                                          ______________________________________                                    

FIG. 1 shows an infrared spectrum of tertiary amine compound No. 1,taken by use of a KBr tablet.

Synthesis Example 2 [Synthesis of Tertiary Amine Compound No. 2 in Table1]

The synthesis procedure in Synthesis Example 1 was applied to obtaintertiary amine compound No. 2 in Table 1.

The melting point of the obtained compound, and the results ofelementary analysis are shown in Table 2.

Synthesis Example 3 [Synthesis of Tertiary Amine Compound No. 5 in Table1]

The synthesis procedure in Synthesis Example 1 was applied to obtaintertiary amine compound No. 5 in Table 1.

The melting point of the obtained compound, and the results ofelementary analysis are shown in Table 2.

Synthesis Example 4 [Synthesis of Tertiary Amine Compound No. 6 in Table1]

The synthesis procedure in Synthesis Example 1 was applied to obtaintertiary amine compound No. 4 in Table 1.

The melting point of the obtained compound, and the results ofelementary analysis are shown in Table 2.

The infrared absorption spectrum chart taken by the KBr tablet method isshown in FIG. 2.

Synthesis Example 5 [Synthesis of Tertiary Amine Compound No. 14 inTable 1]

The synthesis procedure in Synthesis Example 1 was applied to obtaintertiary amine compound No. 14 in Table 1.

The melting point of the obtained compound, and the results ofelementary analysis are shown in Table 2.

Synthesis Example 6 [Synthesis of Tertiary Amine Compound No. 9 in Table1]

The synthesis procedure in Synthesis Example 1 was applied to obtaintertiary amine compound No. 9 in Table 1.

The melting point of the obtained compound, and the results ofelementary analysis are shown in Table 2.

Synthesis Example 7 [Synthesis of Tertiary Amine Compound No. 10 inTable 1]

The synthesis procedure in Synthesis Example 1 was applied to obtaintertiary amine compound No. 10 in Table 1.

The melting point of the obtained compound, and the results ofelementary analysis are shown in Table 2.

The infrared absorption spectrum chart taken by the KBr tablet method isshown in FIG. 3.

Synthesis Example 8 [Synthesis of Tertiary Amine Compound No. 8 in Table1]

The synthesis procedure in Synthesis Example 1 was applied to obtaintertiary amine compound No. 8 in Table 1.

The melting point of the obtained compound, and the results ofelementary analysis are shown in Table 2.

The infrared absorption spectrum chart taken by the KBr tablet method isshown in FIG. 4.

Synthesis Example 9 [Synthesis of Tertiary Amine Compound No. 12 inTable 1]

The synthesis procedure in Synthesis Example 1 was applied to obtaintertiary amine compound No. 12 in Table 1.

The melting point of the obtained compound, and the results ofelementary analysis are shown in Table 2.

The infrared absorption spectrum chart taken by the KBr tablet method isshown in FIG. 5.

Synthesis Example 10 [Synthesis of Tertiary Amine Compound No. 13 inTable 1]

The synthesis procedure in Synthesis Example 1 was applied to obtaintertiary amine compound No. 13 in Table 1.

The the melting point of the obtained compound, and the results ofelementary analysis are shown in Table 2.

The infrared absorption spectrum chart taken by the KBr tablet method isshown in FIG. 6.

Synthesis Example 11 [Synthesis of Tertiary Amine Compound No. 16 inTable 1]

The synthesis procedure in Synthesis Example 1 was applied to obtaintertiary amine compound No. 16 in Table 1.

The melting point of the obtained compound, and the results ofelementary analysis are shown in Table 2.

Synthesis Example 12 [Synthesis of Tertiary Amine Compound No. 15 inTable 1]

The synthesis procedure in Synthesis Example 1 was applied to obtaintertiary amine compound No. 15 in Table 1.

The melting point of the obtained compound, and the results ofelementary analysis are shown in Table 2.

Synthesis Example 13 [Synthesis of Tertiary Amine Compound No. 17 inTable 1]

The synthesis procedure in Synthesis Example 1 was applied to obtaintertiary amine compound No. 17 in Table 1.

The melting point of the obtained compound, and the results ofelementary analysis are shown in Table 2.

The infrared absorption spectrum chart taken by the KBr tablet method isshown in FIG. 7.

Synthesis Example 14 [Synthesis of Tertiary Amine Compound No. 11 inTable 1]

The synthesis procedure in Synthesis Example 1 was applied to obtaintertiary amine compound No. 11 in Table 1.

The melting point of the obtained compound, and the results ofelementary analysis are shown in Table 2.

                                      TABLE 2                                     __________________________________________________________________________     ##STR27##                                                                                                                       Elementary Analysis        Synthesis                                                                          Compound                               Melting Point                                                                        Found (Calculated)         Example                                                                            No.   Ar               R.sup.1 R.sup.2 (°C.)                                                                         % C % H %                  __________________________________________________________________________                                                               N                   2    2                                                                                   ##STR28##       3-CH.sub.3                                                                            3-CH.sub.3                                                                            136.5-137.5                                                                          90.65 (90.64)                                                                     5.57 (5.83)                                                                       3.61 (3.53)         3    5                                                                                   ##STR29##       4-CH.sub.3                                                                            4-CH.sub.3                                                                            239.0-240.0                                                                          90.78 (90.74)                                                                      6.03 (5.95)                                                                      3.56 (3.31)         4    6                                                                                   ##STR30##       3-CH.sub.3                                                                            3-CH.sub.3                                                                            173.0-174.0                                                                          90.81 (90.74)                                                                     5.98 (5.95)                                                                       3.10 (3.31)         5   14                                                                                   ##STR31##       4-CH.sub.3                                                                            4-CH.sub.3                                                                            150.5-151.5                                                                          90.21 (90.04)                                                                     6.14 (6.21)                                                                       3.68 (3.75)         6    9                                                                                   ##STR32##       4-CH.sub.3                                                                            4-CH.sub.3                                                                            Oily   89.22 (89.11)                                                                     6.60 (6.56)                                                                       4.26 (4.33)         7   10                                                                                   ##STR33##       4-C.sub.6 H.sub.4 CH.sub.3 (P)                                                        4-C.sub.6 H.sub.4 CH.sub.3 (P)                                                        139.0-140.0                                                                          91.06 (90.90)                                                                     6.05 (6.16)                                                                       2.78 (2.95)         8    8                                                                                   ##STR34##       4-CH.sub.3                                                                            4-CH.sub.3                                                                            127.0-128.0                                                                          89.19 (89.11)                                                                     6.32 (6.56)                                                                       4.32 (4.33)         9   12                                                                                   ##STR35##       4-CH.sub.3                                                                            4-CH.sub.3                                                                            137.0-138.0                                                                          90.19 (90.03)                                                                     6.04 (6.22)                                                                       3.59 (3.75)        10   13                                                                                   ##STR36##       4-CH.sub.3                                                                            4-CH.sub.3                                                                            225.5-226.0                                                                          89.95 (90.03)                                                                     6.24 (6.22)                                                                       3.79 (3.75)        11   16                                                                                   ##STR37##       4-CH.sub.3                                                                            4-CH.sub.3                                                                            196.5-197.5                                                                          90.60 (90.64)                                                                     5.60 (5.83)                                                                       3.70 (3.52)        12   15                                                                                   ##STR38##       4-CH.sub.3                                                                            4-CH.sub.3                                                                            130.5-131.5                                                                          89.51 (89.36)                                                                     6.61 (6.63)                                                                       3.98 (4.01)        13   17                                                                                   ##STR39##       3-CH.sub.3                                                                            3-CH.sub.3                                                                            155.5-156.5                                                                          90.81 (90.64)                                                                     5.85 (5.83)                                                                       3.43 (3.52)        14   11                                                                                   ##STR40##       4-CH.sub.3                                                                            4-CH.sub.3                                                                            94.0-95.5                                                                            8.79 (88.97)                                                                      6.89 (6.88)                                                                       4.13 (4.15)        __________________________________________________________________________

Example 1

76 parts by weight of Diane Blue (C.I. Pigment Blue 25, C.I. 21180)serving as a charge generating material, 1260 parts by weight of a 2%tetrahydrofuran solution of a polyester resin (Trademark "Vylon 200"made by Toyobo Company, Ltd.) and 3700 parts by weight oftetrahydrofuran were dispersed and ground in a ball mill pot. The thusprepared dispersion was coated on an aluminum surface of analuminum-deposited polyester film by a doctor blade, and then dried atroom temperature, so that a charge generation layer having a thicknessof about 1 μm was formed on the aluminum-deposited polyester film.

2 parts by weight of tertiary amine compound No. 1 in Table 1 preparedin Synthesis Example 1, and 2 parts by weight of polycarbonate resin(Trademark "Panlite K-1300" made by Teijin Limited) were dissolved in 16parts by weight of tetrahydrofuran to prepare a solution. The resultingsolution was coated on the above formed charge generation layer by adoctor blade, and dried at 80° C. for 2 minutes and then at 120° C. for5 minutes, so that a charge transport layer having a thickness of about20 μm was formed on the charge generation layer. Thus a two-layered typeelectrophotographic photoconductor No. 1 according to the presentinvention was prepared.

Examples 2 to 45

The procedure for Example 1 was repeated except that the Diane Blueserving as a charge generating material and the tertiary amine compoundNo. 1 serving as a charge transporting material employed in Example 1were replaced by the respective charge generating materials and chargetransporting materials listed in the following Table 3, wherebytwo-layered type electrophotographic photoconductors No. 2 to No. 45according to the present invention were prepared.

    TABLE 3        Charge Trans- Photo-  poring Material Conductor  (Tertiary Amine No.     Charge Generating Material Compound No.)      1     ##STR41##       1      2     ##STR42##       1      3     ##STR43##       1      4     ##STR44##       1      5     ##STR45##       1      6     ##STR46##       1   7 B-type Copper Phthalocyanine  1      8     ##STR47##       1      9     ##STR48##       1  10 P-1  2 11 P-2  2 12 P-3  2 13 P-2  5 14 P-2  5 15 P-3  5 16 P-1     7 17 P-2  7 18 P-3  7 19 P-1  8 20 P-2  8 21 P-3  8 22 P-1 12 23 P-2 12     24 P-3 12 25 P-1 13 26 P-2 13 27 P-3 13 28 P-1 16 29 P-2 16 30 P-3 16 31     P-1 17 32 P-2 17 33 P-3 17 34 P-1 10 35 P-2 10 36 P-3 10 37 P-1  3 38     P-2  3 39 P-3  3 40 P-1  4 41 P-2  4 42 P-3  4 43 P-1 11 44 P-2 11 45     P-3 11

Example 46

Selenium was vacuum-deposited on an aluminum plate having a thickness ofabout 300 μm which serves as an electroconductive substrate, so that acharge generation layer having a thickness of about 1 μm was formed onthe aluminum plate.

2 parts by weight of tertiary amine compound No. 1 in Table 1, 3 partsby weight of polyester resin (Trademark "Polyester Adhesive 49000" madeby Du Pont de Nemours, E.I. & Co.) were dissolved in 45 parts by weightof tetrahydrofuran. The resulting solution was coated on the aboveformed charge generation layer by a doctor blade, dried at roomtemperature, and then dried under reduced pressure, so that a chargetransport layer having a thickness of about 10 μm was formed on thecharge generation layer. Thus a two-layered type electrophotographicphotoconductor No. 46 according to the present invention was prepared.

Example 47

A perylene pigment having the following formula was vacuum-deposited onan aluminum plate having a thickness of about 300 μm, so that a chargegeneration layer having a thickness of about 0.6 μm was formed on thealuminum plate: ##STR49##

2 parts by weight of tertiary amine compound No. 1 in Table 1, 3 partsby weight of a polyester resin (Trademark "Polyester Adhesive 49000"made by Du Pont de Nemours, E.I. & Co.) were dissolved in 45 parts byweight of tetrahydrofuran. The resulting solution was coated on theabove formed charge generation layer by a doctor blade, dried at roomtemperature, and then dried under reduced pressure, so that a chargetransport layer having a thickness of about 10 μm was formed on thecharge generation layer. Thus a two-layered type electrophotographicphotoconductor No. 47 according to the present invention was prepared.

Example 48

A mixture of 1 part by weight of the same Diane Blue as employed inExample 1 and 158 parts by weight of tetrahydrofuran was dispersed andground in a ball mill pot to prepare a dispersion. To the thus prepareddispersion, 12 parts by weight of tertiary amine compound No. 1 in Table1 and 18 parts by weight of polyester resin (Trademark "PolyesterAdhesive 49000" made by Du Pont de Nemours, E.I. & Co.) were added toprepare a solution. The resulting solution was coated on analuminum-deposited polyester film by a doctor blade, and dried at 100°C. for 30 minutes, so that a photoconductive layer having a thickness ofabout 16 μm was formed on the electroconductive support. Thus, anelectrophotographic photoconductor No. 48 according to the presentinvention was prepared.

Example 49

The solution for forming a charge transport layer, prepared in Example1, was coated on an aluminum-deposited polyester film by a doctor blade,and dried at 80° C. for 2 minutes and then at 120° C. for 5 minutes, sothat a charge transport layer having a thickness of about 20 μm wasformed on the aluminum-deposited polyester film.

A mixture of 13.5 parts by weight of bisazo pigment (P-2), 5.4 parts byweight of polyvinyl butyral (Trademark "XYHL" made by Union CarbideJapan K.K.), 680 parts by weight of tetrahydrofuran and 1020 parts byweight of ethyl cellosolve was dispersed and ground in a ball mill pot.To this dispersion, 1700 parts by weight of ethyl cellosolve was furtheradded to prepare a solution. The resulting was coated on the aboveformed charge transport layer by spray coating and dried at 100° C. for10 minutes, so that a charge generation layer having a thickness ofabout 0.2 μm was formed on the charge transport layer.

A mixed solution of methanol and n-butanol containing a polyamide resin(Trademark "CM-8000" made by Toray Silicone Co., Ltd.) was coated on theabove formed charge generation layer by spray coating and dried at 120°C. for 30 minutes, so that a protective layer having a thickness ofabout 0.5 μm was formed on the charge generation layer. Thus, atwo-layered type electrophotographic photoconductor No. 49 according tothe present invention was prepared.

Each of the above-prepared electrophotographic photoconductors No. 1through No. 49 according to the present invention was charged negativelyor positively in the dark under application of -6 kV or +6 kV of coronacharge for 20 seconds, using a commercially available electrostaticcopying sheet testing apparatus ("Paper Analyzer Model SP-428" made byKawaguchi Electro Works Co., Ltd.). Then, each electrophotographicphotoconductor was allowed to stand in the dark for 20 seconds withoutapplying any charge thereto, and the surface potential Vpo (V) of thephotoconductor was measured. The photoconductor was then illuminated bya tungsten lamp in such a manner that the illuminance on the illuminatedsurface of the photoconductor was 4.5 lux, and the exposure E_(1/2)lux.sec) required to reduce the initial surface potential Vpo (V) to 1/2the initial surface potential Vpo (V) was measured. The results areshown in Table 4.

                  TABLE 4                                                         ______________________________________                                        Photoconductor No.                                                                            Vpo (V)  E.sub.1/2  (lux · sec)                      ______________________________________                                         1              -1120    1.42                                                  2              -1060    1.25                                                  3              -1095    0.99                                                  4              -1250    2.20                                                  5              -1110    0.83                                                  6              -1025    0.54                                                  7              -1200    1.85                                                  8              -1230    1.52                                                  9              -1050    1.25                                                 10              -1105    0.99                                                 11              -1153    0.96                                                 12              -1133    0.70                                                 13              -1130    0.97                                                 14              -1170    0.94                                                 15              -1080    0.65                                                 16              -1140    0.99                                                 17              -1380    1.46                                                 18              -1181    1.11                                                 19              -1155    0.97                                                 20              -1204    0.96                                                 21              -1100    0.59                                                 22              -1110    1.01                                                 23              -1058    0.90                                                 24              -1026    0.68                                                 25              -1050    0.94                                                 26              -1120    0.88                                                 27              -1080    0.57                                                 28              -1180    0.98                                                 29              -1114    0.90                                                 30               -988    0.60                                                 31              -1120    0.96                                                 32              -1005    0.97                                                 33               -980    0.58                                                 34              -1095    0.98                                                 35              -1164    1.10                                                 36              -1120    0.61                                                 37              -1160    1.02                                                 38              -1375    1.13                                                 39              -1138    0.88                                                 40              -1085    0.98                                                 41              -1328    0.99                                                 42               - 987   0.50                                                 43              -1250    1.15                                                 44              -1314    1.14                                                 45              -1120    0.76                                                 46               -940    2.10                                                 47              -1280    3.70                                                 48              +1290    1.70                                                 49              +1285    0.95                                                 ______________________________________                                    

Each of the above-mentioned electrophotographic photoconductorsaccording to the present invention was incorporated in a commerciallyavailable electrophotographic copying machine and charged negatively orpositively. Then it was exposed to the light through an original to forma latent electrostatic image on the surface of the photoconductor. Thethus formed latent electrostatic image was developed by a dry-typedeveloper to a visible image. The resulting visible image wastransferred to a sheet of plain paper and fixed thereon, so that a cleartransferred image was formed. In the case where a wet-type developer wasemployed, a clear image was formed likewise.

Comparative Example 1

Example 1 was repeated except that the charge generating material usedin Example 1 was replaced by a charge generating material P-2 shown inTable 3, and the tertiary amine compound No. 1 used as the chargetransporting material in Example 1 was replaced by4,4',4"-trimethyltriphenyl amine, whereby a comparativeelectrophotographic photoconductor was prepared.

The electrophotographic photoconductor thus obtained was evaluated inthe same manner as described above, and V_(po) and E_(1/2) weremeasured. In addition, the residual potential (Vr) 30 seconds afterillumination was also measured.

The results are shown in Table 5 along with the data with respect toelectrophotographic photoconductor No. 5 according to the presentinvention for comparison.

                  TABLE 5                                                         ______________________________________                                                      V.sub.po E.sub.1/2                                                                            Vr                                              ______________________________________                                        Photoconductor No. 5                                                                          -1110      0.83     0                                         Comp. Photoconductor                                                                          -1287      1.24   -129                                        ______________________________________                                    

The above data demonstrate that the electrophotographic photoconductorNo. 5 according to the present invention has a higher photosensitivity,indicated by E_(1/2), in comparison with the comparative photoconductor,and has no residual potential Vr.

The electrophotographic photoconductors according to the presentinvention are excellent in the photoconductive characteristics.Moreover, they are thermally and mechanically stable, and can beproduced inexpensively.

What is claimed is:
 1. A charge transporting material comprising atertiary amine compound having a condensed polycyclic hydrocarbon groupof formula (I): ##STR50## wherein A¹ or A² is a linear or branched alkylgroup having 1 to 12 carbon atoms, which may have a substituent and Arrepresents an unsubstituted or substituted condensed polycyclichydrocarbon group selected from the group consisting of a pentalenylgroup, an indenyl group, an azulenyl group, a heptalenyl group, abiphenylenyl group, an as-indacenyl group, an s-indacenyl group, anacenaphthenyl group, a pleiadenyl group, an acenaphthenyl group, aphenalenyl group, a phenanthryl group, a 1-anthryl group, a 2-anthrylgroup, a 2-naphthyl group, a fluoranthenyl group, an acephenanthrylenylgroup, an aceanthrylenyl group, a triphenylenyl group, a chrysenyl groupand a naphthacenyl group wherein said substituent on Ar is selected fromthe group consisting of halogen, a cyano group, a nitro group, a linearor branched C₁₋₁₂ alkyl group which may have a substituent selected froma fluorine group, a hydroxyl group, a cyano group, a C₁₋₄ alkoxy or aphenyl group which may be substituted by halogen, a C₁₋₁₄ alkyl group ora C₁₋₄ alkoxy group.
 2. The charge transporting material as claimed inclaim 1, wherein said substituent of said alkyl group is selected fromthe group consisting of fluorine, a hydroxyl group, a cyano group, analkoxyl group having 1 to 4 carbon atoms, and a phenyl group which mayhave a substituent.
 3. The charge transporting material as claimed inclaim 2, wherein said substituent of said phenyl group is selected fromthe group consisting of a halogen, an alkyl group having 1 to 4 carbonatoms, and alkoxyl group having 1 to 4 carbon atoms.
 4. The chargetransporting material as claimed in claim 1, wherein said condensedpolycyclic hydrocarbon group represented by Ar is a group having a ringconsisting of 18 or less carbon atoms, which may have a substituent. 5.The charge transporting material as claimed in claim 4, wherein saidsubstituent of said condensed polycyclic hydrocarbon group is selectedfrom the group consisting of a halogen, a cyano group and a nitro group.6. The charge transporting material as claimed in claim 4, wherein saidsubstituent of said condensed polycyclic hydrocarbon group is a linearor branched alkyl group having 1 to 12 carbon atoms, which may have asubstituent.
 7. The charge transporting material as claimed in claim 6,wherein said substituent of said alkyl group is selected from the groupconsisting of fluorine, a hydroxyl group, a cyano group, an alkoxylgroup having 1 to 4 carbon atoms, and a phenyl group which may have asubstituent.
 8. The charge transporting material as claimed in claim 7,wherein said substituent of said phenyl group is selected from the groupconsisting of a halogen, an alkyl group having 1 to 4 carbon atoms, andan alkoxyl group having 1 to 4 carbon atoms.
 9. The charge transportingmaterial as claimed in claim 4, wherein said substituent of saidcondensed polycyclic hydrocarbon group is an alkoxyl group having 1 to12 carbon atoms, which may have a substituent.
 10. The chargetransporting material as claimed in claim 9, wherein said substituent ofsaid alkoxyl group is selected from the group consisting of fluorine, ahydroxyl group, a cyano group, an alkoxyl group having 1 to 4 carbonatoms, and a phenyl group which may have a substituent.
 11. The chargetransporting material as claimed in claim 10, wherein said substituentof said phenyl group is selected from the group consisting of a halogen,an alkyl group having 1 to 4 carbon atoms, and an alkoxyl group having 1to 4 carbon atoms.
 12. The charge transporting material as claimed inclaim 14, wherein said substituent of said condensed polycyclichydrocarbon group is an aryloxy group.
 13. The charge transportingmaterial as claimed in claim 12, wherein said aryloxy group is selectedfrom the group consisting of a phenoxy group, a 1-naphthyloxy group, a2-naphthyloxy group, a 4-methylphenoxy group, a 4-methoxyphenoxy group,a 4-chlorophenoxy group and a 6-methyl-2-naphthyloxy group.
 14. Thecharge transporting material as claimed in claim 4, wherein saidsubstituent of said condensed polycyclic hydrocarbon group is a grouprepresented by ##STR51## wherein R² and R³ each independently representhydrogen, a linear or branched alkyl group having 1 to 12 carbon atoms,or an aryl group which may have a substituent, and R² and R³ may form aring.
 15. The charge transporting material as claimed in claim 14,wherein said substituent of said alkyl group is selected from the groupconsisting of fluorine, a hydroxyl group, a cyano group, an alkoxylgroup having 1 to 4 carbon atoms, and a phenyl group which may have asubstituent.
 16. The charge transporting material as claimed in claim14, wherein said substituent of said aryl group is selected from thegroup consisting of an alkyl group having 1 to 4 carbon atoms, analkoxyl group having 1 to 4 carbon atoms and a halogen.
 17. The chargetransporting material as claimed in claim 4, wherein said substituent ofsaid condensed polycyclic hydrocarbon group is an alkylenedioxy group.